While moving from one window to another window in a mobile native application we can use different transition animation style.
There are few posible transition styles described below for iPhone app using Appcelerator Titanium.

//Different transition style
var transitionStyle = {
curlDown : Ti.UI.iPhone.AnimationStyle.CURL_DOWN,
//Curl downwards during a transition animation
curlUp : Ti.UI.iPhone.AnimationStyle.CURL_UP,
//Curl upwards during a transition animation
flipFromLeft : Ti.UI.iPhone.AnimationStyle.FLIP_FROM_LEFT,
//Flip from left to right during a transition animation
flipFromRight: Ti.UI.iPhone.AnimationStyle.FLIP_FROM_RIGHT,
//Flip from right to left during a transition animation
noStyle : Ti.UI.iPhone.AnimationStyle.NONE
//No animation
}
Suppose we are in login page and after login we need to move on home page which is home.js
//Define home window
var homeWindow = Ti.UI.createWindow({
url : 'home.js'//define path of the page that need to open
});
//Open the home page
homeWindow.open({transition : transitionStyle.curlDown});//Will open the home page with curl down style

So in this was we can use different transition style from the above styles while moving from one window to another.